Re: [PATCH v6 5/6] arm64: add SIGSYS siginfo for compat task

Kees Cook
2014-08-21T17:54:11Z

On Thu, Aug 21, 2014 at 3:56 AM, AKASHI Takahiro
<takahiro.akashi@linaro.org> wrote:
> SIGSYS is primarily used in secure computing to notify tracer.
> This patch allows signal handler on compat task to get correct information
> with SA_SYSINFO specified when this signal is delivered.
>
> Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org>

I'm unable to test this myself, but if you've got the test suite
passing in compat mode, then this patch must be correct. :)

Reviewed-by: Kees Cook <keescook@chromium.org>

-Kees

> ---
> arch/arm64/include/asm/compat.h | 7 +++++++
> arch/arm64/kernel/signal32.c | 8 ++++++++
> 2 files changed, 15 insertions(+)
>
> diff --git a/arch/arm64/include/asm/compat.h b/arch/arm64/include/asm/compat.h
> index 253e33b..c877915 100644
> --- a/arch/arm64/include/asm/compat.h
> +++ b/arch/arm64/include/asm/compat.h
> @@ -205,6 +205,13 @@ typedef struct compat_siginfo {
> compat_long_t _band; /* POLL_IN, POLL_OUT, POLL_MSG */
> int _fd;
> } _sigpoll;
> +
> + /* SIGSYS */
> + struct {
> + compat_uptr_t _call_addr; /* calling user insn */
> + int _syscall; /* triggering system call number */
> + unsigned int _arch; /* AUDIT_ARCH_* of syscall */
> + } _sigsys;
> } _sifields;
> } compat_siginfo_t;
>
> diff --git a/arch/arm64/kernel/signal32.c b/arch/arm64/kernel/signal32.c
> index 1b9ad02..aa550d6 100644
> --- a/arch/arm64/kernel/signal32.c
> +++ b/arch/arm64/kernel/signal32.c
> @@ -186,6 +186,14 @@ int copy_siginfo_to_user32(compat_siginfo_t __user *to, const siginfo_t *from)
> err |= __put_user(from->si_uid, &to->si_uid);
> err |= __put_user((compat_uptr_t)(unsigned long)from->si_ptr, &to->si_ptr);
> break;
> +#ifdef __ARCH_SIGSYS
> + case __SI_SYS:
> + err |= __put_user((compat_uptr_t)(unsigned long)
> + from->si_call_addr, &to->si_call_addr);
> + err |= __put_user(from->si_syscall, &to->si_syscall);
> + err |= __put_user(from->si_arch, &to->si_arch);
> + break;
> +#endif
> default: /* this is just in case for now ... */
> err |= __put_user(from->si_pid, &to->si_pid);
> err |= __put_user(from->si_uid, &to->si_uid);
> --
> 1.7.9.5
>

--
Kees Cook
Chrome OS Security